NK Cell Cytokine Production Research Articles

NKG2D-bispecific enhances NK and CD8+ T cell antitumor immunity

BackgroundCancer immunotherapy approaches that elicit immune cell responses, including T and NK cells, have revolutionized the field of oncology. However, immunosuppressive mechanisms restrain immune cell activation within solid tumors so additional strategies to augment activity are required.MethodsWe identified the co-stimulatory receptor NKG2D as a target based on its expression on a large proportion of CD8+ tumor infiltrating lymphocytes (TILs) from breast cancer patient samples. Human and murine surrogate NKG2D co-stimulatory receptor-bispecifics (CRB) that bind NKG2D on NK and CD8+ T cells as well as HER2 on breast cancer cells (HER2-CRB) were developed as a proof of concept for targeting this signaling axis in vitro and in vivo.ResultsHER2-CRB enhanced NK cell activation and cytokine production when co-cultured with HER2 expressing breast cancer cell lines. HER2-CRB when combined with a T cell-dependent-bispecific (TDB) antibody that synthetically activates T cells by crosslinking CD3 to HER2 (HER2-TDB), enhanced T cell cytotoxicity, cytokine production and in vivo antitumor activity. A mouse surrogate HER2-CRB (mHER2-CRB) improved in vivo efficacy of HER2-TDB and augmented NK as well as T cell activation, cytokine production and effector CD8+ T cell differentiation.ConclusionWe demonstrate that targeting NKG2D with bispecific antibodies (BsAbs) is an effective approach to augment NK and CD8+ T cell antitumor immune responses. Given the large number of ongoing clinical trials leveraging NK and T cells for cancer immunotherapy, NKG2D-bispecifics have broad combinatorial potential.

P-436 Uterine NK cells underexpress KIR2DL1/S1 and LILRB1 receptors recognizing HLA-C2 and HLA-G on extravillous trophoblasts in reproductive failure

Abstract Study question Is there a difference in frequency, receptor expression and cytokine production of uterine NK cells (uNK) subpopulations in women with reproductive failure compared to controls? Summary answer Reproductive failure is associated with global underexpression of uNK receptors interacting with extravillous trophoblasts (EVT) that may result in defective implantation and placentation. What is known already A significant proportion of infertility, recurrent miscarriage and recurrent implantation failure are unexplained. This may be caused by immunological dysfunction at the maternal-fetal interface resulting in defective implantation and placentation. uNK is thought to play an important role in early pregnancy by cross-talking with EVT via KIR/HLA-C, LILRB1/HLA-G and CD94/HLA-E interactions to regulate EVT invasion and spiral arteriole remodeling in the decidua. Dysregulation of uNK function may cause reproductive failure; however it is unclear whether NK cell over- or under-activation is the pathology. Previous studies have been conducted on uNK obtained after miscarriage, which may be confounded by inflammatory processes. Study design, size, duration Here, we conducted a cross-sectional study to assess frequency, phenotype and function of matched pNK and uNK during the window of implantation in 16 women with reproductive failure compared to 11 controls. Women with reproductive failure cohort included unexplained subfertility (9), recurrent miscarriage (4) and recurrent implantation failure (3). The women were subsequently followed up after IVF and comparison made between women who did and did not fall pregnant. Participants/materials, setting, methods Matched peripheral blood and endometrial tissue were obtained from participants during the mid-secretory phase. Samples were accurately timed for 7-9 days after ovulation by urine LH test or histological dating. Flow cytometry was used to assess the frequency, phenotype and function. Phenotype was measured by KIR, LILRB1 and CD94 and receptor expression. Function was measured by degranulation (anti-CD107a internalization) and cytokine production (TNF-α, GM-CSF, IFN-γ and IL-8), with and without stimulation by PMA and ionomycin. Main results and the role of chance The expression of KIR2DL1/S1 and LILRB1 were significantly lower in reproductive failure group for both uNK (total uNK, uNK2 and 3) and pNK. The common finding in both uNK and pNK suggests that this is not tissue specific and may have an immunogenetic aetiology. We have previously found that degranulation peaks during secretory phase and in first trimester pregnancy. TNF-α production was also found to peak in secretory phase. Here, we found that degranulation activity of total uNK, as well as TNF-α production all uNK subsets was significantly lower in reproductive failure compared to control group. However, no significant difference was found in women in the reproductive failure cohort who fell pregnant compared to women who did not fall pregnant or miscarried after IVF. Contrary to findings from previous studies, we have not found any difference in uNK or pNK frequencies in any of the groups that were examined. Taken together, our findings suggest that reproductive failure is associated with global underexpression of receptors important for interaction with HLA-C and HLA-G on EVT, resulting in reduced uNK activation. This in turn may lead to dysregulation of implantation and placenta formation in early stage of pregnancy. Limitations, reasons for caution KIR2DL1/S1 antibody used does not distinguish between KIR2DL1 and KIR2DS1 which exerts inhibitory and activating effects respectively. Larger cohort studies on both pNK and uNK that consider KIR2DL1 and KIR2DS1 separately is needed to confirm which of these receptors are specifically reduced in reproductive failure. Wider implications of the findings Overall, our findings suggest that reproductive failure is associated with global underexpression of NK cell receptors leading to impaired implantation and placentation. This is the first study to examine uNK subsets during window of implantation and will serve as a platform to focus on particular uNK subsets in future studies. Trial registration number Not applicable

CD19-Specific CAR NK Cells Coexpressing IL-21 Exhibit Superior Expansion and Antitumor Activity Against CD19-Postive Lymphoma

Background Chimeric antigen receptor (CAR) expressing NK cells induce robust antitumor responses in patients with hematologic malignancies but have limited persistent without cytokines supplement. IL-15 and IL-21 promote NK cell expansion, survival, and possess both overlapping and distinctive functions. CAR NK cells engineered to express IL-15 have shown long-term persistence and potent antitumor activity, however, the pleiotropic effects of IL-21 on CAR NK cell-mediated tumor rejection are lacking. Therefore, we compared the therapeutic potency of CD19-specific human NK cells that constitutively express IL-15 or IL-21. Methods The codon-optimized minigene encoding cytokine IL-21 or IL-15, linked with CD19-CAR containing 4-1BB costimulatory domain by a P2A sequence were synthesized and sub-cloned into the pSFG retroviral vector yielding the BBz.IL21 or BBz.IL15 retroviral construct. To produce CD19-CAR retrovirus, 293T/17 cells were transfected with a combination of plasmids containing CAR constructs, RDF plasmid and PegPam3 plasmid. Human peripheral blood NK cells isolated from healthy volunteer donors were stimulated with CD16/CD137 mAb and expanded with 500 IU/ml IL-2 (PeproTech) for 5 days before transduced with CAR retrovirus in plates coated with RetroNectin. The expression of CAR, phenotype, degranulation, cytokine production, and cytotoxicity of CAR NK cells were analyzed on day 3 post transduction. To measure IL-15 and IL-21 production, supernatants were collected from CAR NK cells cultured in the absence of IL-2 for 24h and evaluated by ELISA. Results After transduction, all constructs were stably expressed by NK cells, with construct containing IL-21 (71.23 ± 4.05 %, n = 3) demonstrating higher transduction efficiency compared with the BBz.IL15 (61.13 ± 3.43 %), but slightly lower than the BBz construct (79.63 ± 3.83 %). High levels of IL-21 were found in the supernatant of BBz.IL21 NK cells after resting 24h (3464 ± 199 pg/ml), while no detectable IL-21 was observed on BBz and BBz.IL15 NK cells. NK cells expressing BBz.IL15 produced significantly more IL-15 than BBz.IL21 and BBz NK cells as baseline (BBz.IL15: 213 ± 14 pg/ml, BBz.IL21: 61.86± 4 pg/ml, BBz: 60.56 ± 11 pg/ml). Given that IL-15 or IL-21 could potentially induce antigen-independent NK cell proliferation, we compared the ability of each NK-cell group to maintain growth in the presence of IL-2. The expansion of CAR NK cells expressing IL-21 was significantly higher than that of CAR NK cells expressing IL-15, while the number of BBz.IL15 NK cells and BBz NK cells were comparable (fold expansion in 5 days: BBz.IL21: 26.6 fold, BBz.IL15: 15.9 fold, BBz: 17.2 fold), suggesting a synergistic effect of IL-21 and IL-2 on CAR NK cell expansion. BBz.IL21 NK cells shared a similar immunophenotypic profile to BBz.IL15 NK cells, as the expression of inhibitory receptors PD1, LAG3, TIM3 and NKG2A, as well as activation receptors NKG2D and CD69 were comparable. CAR engagement by CD19-postive Raji cells specifically induced cytokines production by CD19-CAR NK cells but not by control NK cells. IL-21 coexpression significantly enhanced IFN-γ and TNF-α production compared with CAR NK cells as well as CAR NK cells expressing IL-15 (BBz.IL21 vs. BBz.IL15, P < 0.05; BBz.IL21 vs. BBz, P < 0.05; BBz.IL15 vs. BBz, P > 0.05). Moreover, a higher percentage of degranulated NK cells was observed on BBz.IL21 NK cells compared to BBz.IL15 NK cells and BBz NK cells. To confirm this observation, NK cells were cocultured with Raji cells at various E:T ratios for 6h. CAR NK cells expressing IL-21 showed superior cytotoxicity, compared to CAR NK cells expressing IL-15. Conclusion CD19-CAR NK cells engineered to express IL-21 gene produced high levels of IL-21 during cultivation and enabled greater ex vivo expansion of CAR NK cells compared with CAR NK cells expressing IL-15. IL-21 coexpression induced a significant increase in IFN-γ, TNF-α production and degranulation compared with IL-15 coexpression, resulting in enhanced antitumor activity of CD19-CAR NK cells against CD19-postive lymphoma.

Disruption of SOCS1 Promotes the Antitumor Activity of CD19-Specific CAR NK Cells Coexpressing IL-15

Background Chimeric antigen receptor (CAR) expressing NK cells exhibit robust antitumor responses in patients with hematologic malignancies but have limited persistent without cytokines supplement. Interleukin-15 (IL-15) promotes NK cells expansion and survival, while IL-15 signaling is often inhibited by the suppressor of cytokine signaling (SOCS) proteins (CIS, SOCS1-7), which is rapidly induced in response to IL-15 and negatively regulates cytokine signaling through the JAK/STAT pathway in NK cells. We hypothesized that SOCS1 would be a logical checkpoint to target in human NK cells to increase their persistence and thereby enhance their antitumor potency. Here, we devised a strategy that couples targeting the SOCS1 protein, with CD19-specific human NK cells that constitutively express IL-15. Method Firstly, we evaluated the SOCS1 mRNA expression levels on NK cells after cultured with or without IL-15 for 6 or 24 hours by reverse transcription polymerase chain reaction (RT-PCR). The retroviral vector encoding CAR19.4-1BB-zeta-2A-IL-15 (named BBz.IL-15) and the production of transient retroviral supernatants have been previously described. Human peripheral blood NK cells isolated from healthy volunteer donors were stimulated with CD16/CD137 mAb and expanded with 500 IU/ml IL-2 (PeproTech) for 5 days before transduced with CAR retrovirus in plates coated with RetroNectin. CAR expression on NK cells was determined by flow cytometry, and IL-15 secretion was measured by ELISA. Knockout (KO) of SOCS1 by CRISPR/Cas9 using the Neon transfection system was performed on day 3 post transduction in both non-transduced NK cells (NT-NK) and CAR-transduced NK cells (CAR-NK). To assess KO efficiency, we used polymerase chain reaction (PCR) gel electrophoresis, western blot, and Sanger sequencing. The degranulation, cytokine production, and cytotoxicity of CAR NK cells were analyzed on day 7 post electroporation. Results The expression of SOCS1 on NK cells was significantly induced within 6 hours of IL-15 treatment. Our approach for combined retroviral transduction with the anti-CD19 CAR and RNP-mediated gene editing of SOCS1 showed that surface expression of the CAR was maintained on NK cells in culture, with construct containing BBz.IL15 (37.18 ± 11.71%) demonstrating comparable transduction efficiency compared with the BBz construct (45.48 ± 10.54%) (P＞0.05), and the efficiency of SOCS1 KO was high in both the nontransduced (NT) control and CAR-expressing NK cells by TIDE and remained stable over time. When tested against CD19-postive Raji cells, SOCS1 KO BBz.IL-15 NK cells produced more IFN-γ and TFN-α, and displayed greater degranulation (CD107a) against their targets than did their BBz.IL-15 NK controls (BBz.IL-15 SOCS1 KO vs BBz.IL-15 control: 15.75±2.05% vs 7.93±0.47% for IFN-γ, P=0.032; 6.27±1.27% vs 1.88±0.26% for TFN-α, P=0.04; 23.25±2.33% vs 12.35±2.33% for CD107a, P=0.042). However, there was no significant difference between the SOCS1 KO BBz. or NT NK cells and their respective BBz. and NT controls regarding IFN-γ and TFN-α production and degranulation (BBz.SOCS1 KO vs BBz.control: 16.95±5.30% vs 16.85±8.70% for IFN-γ, P＞0.05; 6.83±2.98% vs 4.06±2.47% for TFN-α, P＞0.05; 26.65±7.14% vs 25.8±2.12% for CD107a, P＞0.05) (NT SOCS1 KO vs NT control: 21.75±6.58% vs 7.5±2.18% for IFN-γ, P＞0.05; 7.23±3.46% vs 1.58±0.03% for TFN-α, P＞0.05; 15.05±3.46% vs 6.84±2.15% for CD107a, P＞0.05). To confirm this observation, NK cells were cocultured with Raji cells at various E:T ratios for 6h. SOCS1 KO NK cells could kill the tumors more efficiently in comparison to the control. Proliferation data showed the SOCS1 KO NK cells can grow faster than the control group. Conclusion In conclusion, the results demonstrate that SOCS1 might be a potential target for genetic modification to improve activity of CAR- NK cells.

Anti CD161 Antibody IMT-009 Is a Novel Immunotherapeutic Agent That Effectively Blocks the Inhibitory CLEC2D/CD161 Axis in CLEC2D+ B Cell Hematological Malignancies Reinvigorating T and NK Cell Function Leading to Anti-Tumor Benefit

Background: The CLEC2D/CD161 axis is a ligand-receptor pathway that has been shown to inhibit both T and NK cell function 1,2. CD161 is a C-type lectin-like receptor, which is expressed on NK cells and subsets of both CD4 + and CD8 + T cells. The tumor infiltrating CD161+ T cells have high cytotoxic potential and display an NK cell-like signature 2. Its ligand CLEC2D is expressed on the surface of both malignant cells and immune cells including germinal center B cells, activated T cells and tumor associated macrophages. Owing to its expression in germinal center B cells, CLEC2D is highly expressed in multiple types of B cell lymphomas including Diffuse Large B Cell Lymphoma (DLBCL), Follicular Lymphoma and Burkitt lymphoma 3. Furthermore, subset of infiltrated T cells in these lymphomas are CD161+ making this axis a promising novel target for immunotherapeutic intervention in hematological malignancies (Fig1). Immunitas has developed IMT-009, a monoclonal, Fc silent, fully human IgG1, high affinity antibody to CD161 that selectively blocks its interaction with CLEC2D. We show that IMT-009 effectively reverses CLEC2D-mediated inhibition and restores NK cell and T cell functions, including antigen specific T cell mediated cytotoxicity to lymphoma cell lines. Furthermore, IMT-009 shows monotherapy benefit in reducing tumor burden in a human B cell lymphoma model engrafted in humanized mice in vivo. IMT-009 is currently being evaluated in a Phase 1/2a clinical trial in both solid tumors and heme malignancies. Results: IMT-009 is a highly selective antibody to CD161 that strongly blocks its interaction with CLEC2D. In presence of CLEC2D-expressing target cells, NK cell degranulation, cytokine production and cellular cytotoxicity towards lymphoma tumor targets is highly suppressed which is overcome by treatment with IMT-009. Similarly, IMT-009 reversed CLEC2D-mediated inhibition and restored T cell activity (TCR signaling, cytokine production) in a Jurkat cell reporter system, and enhanced polyfunctionality of primary antigen-specific human T cells shown by secretion of TNF-α, IL-2, and IFN-γ, and direct T cell mediated cytotoxicity. IMT-009 also released CD161-mediated suppression of antigen recall response by PBMC derived effector memory CD161+ CD4+ T cells, resulting in an increased frequency of CD161+ IFN-γ+ cells and an increase in their proliferation. These data together show that IMT-009 is highly effective in overcoming CLEC2D mediated suppression of both T and NK cell functions. To prioritize indications that will likely benefit from IMT-009, we performed IHC for CLEC2D in a diverse set of tumor indications and found that B cell lymphomas of various subtypes have high CLEC2D protein expression by H score. Also, DLBCL was found to have the second highest median RNA expression of CLEC2D in TCGA. Furthermore, analysis of publicly available single-cell RNA-sequencing (scRNA-seq) data from B cell lymphoma including CNS lymphoma revealed CLEC2D to be highly expressed within the B lineage cells including the abundant malignant cell population (Fig2). KLRB1 (gene encoding for CD161) was also found to be expressed on a subset of tumor infiltrating CD4 and CD8 T cells in these datasets (Fig2). To confirm this, we tested CD161 expression in B cell lymphomas by immunofluorescence. Results showed CD161+ cells infiltrated in Hodgkin Lymphoma, and post-R-CHOP treated DLBCL, highlighting the potential sensitivity of these malignancies to IMT-009 treatment. Together, these results indicate that B cell lymphomas may exhibit an immunosuppressive environment mediated by the CLEC2D/CD161 axis. To test the anti-tumor benefit of IMT-009 in a human B cell lymphoma model, we treated CD34+ humanized mice implanted with Raji, a Burkitt lymphoma cell line with IMT-009. The group of mice treated with IMT-009 had a mean tumor growth inhibition of 35% and the anti-tumor response correlated with increased frequency of CD161+ T and NK cells. We further show that IMT-009 can synergize with Rituximab in NK cell mediated killing of B cell lymphoma cell lines in vitro. Conclusion: B cell malignancies tend to respond poorly to anti-PD-1 therapy 4,5. This lack of efficacy could be driven by a highly immunosuppressive environment mediated by the CLEC2D/CD161 axis. Our results support evaluation of IMT-009 as a novel cancer immunotherapy to disrupt CLEC2D/CD161 signaling, with strong therapeutic potential in lymphomas.

MEF2C is a critical regulator of human NK cell metabolism.

Abstract Natural killer (NK) cells are critical for the first line of defense against viral infection and malignancy. While the transcriptional and epigenetic regulation of activated NK cells is well characterized in mice, these processes are not yet fully understood in human NK cells. We performed a targeted CRISPR/Cas9 ribonucleoprotein (RNP) transcription factor screen in mature primary human NK cells to identify putative transcription factors required for optimal effector function. The transcription factor myocyte enhancer factor 2C (MEF2C) emerged as a previously unidentified regulator of NK cell homeostasis, cytokine production, and cytotoxicity. MEF2C-deficient NK cells activated with IL-2 and IL-15 displayed impaired proliferation, degranulation, and production of granzyme B. CRISPR-mediated deletion of MEF2C resulted in disrupted glycolysis and oxidative phosphorylation using both SCENITH and Seahorse extracellular flux analysis. Liquid chromatography/mass spectrometry (LC/MS)-based metabolomics of MEF2C-deficient NK cells revealed reductions in the metabolites glyceraldehyde-3-phosphate and a-ketoglutarate/succinate, accompanied by increased accumulation of lipid metabolism products including phosphorylethanolamine and saturated long-chain fatty acids. In vivo, CRISPR/Cas9 RNP-mediated disruption of MEF2C expression in mouse NK cells resulted in decreased expansion during mouse cytomegalovirus infection. Together, these studies reveal MEF2C as a novel regulator of NK cell effector function through control of multiple critical cell-intrinsic metabolic pathways.

Abstract LB337: Inhibition of the E3 ligase CBL-B enhances the effector function and proliferation of natural killer cells

Abstract The E3 ubiquitin ligase CBL-B is a master regulator of effector T cells through its downstream regulation of T-cell receptor and co-stimulatory stimulation, but it has also been shown to play a negative feedback role in NK cells. CBL-B depletion enhances the production of IFNγ and the cytotoxicity of activated NK cells. Similar to the effect of depleting CD8 T cells in mice, depletion of NK cells abolishes the tumor growth delay observed in Cbl-b-/- mice. With emerging data supporting the potential role of exogenous NK cells in anti-tumor immunity, inhibition of CBL-B represents a promising approach to enhance both adaptive and innate immunity for cancer immunotherapy. Using one of our small molecules, allosteric CBL-B inhibitors, HOT-A, we demonstrated that CBL-B inhibition enhanced NK activation, IFNγ production and granzyme B secretion in response to the various stimulation conditions, including cytokines (such as IL-15 and IL12 + IL-18) and stimulatory receptors (such as NKp30 and NKG2D + CD244). NK cell proliferation was also enhanced in the presence of HOT-A. Single cell analysis further suggested that HOT-A increased NK polyfunctional cytokine expression during IL-12 + IL-18 activation. In a coculture system of NK cells and K562 target cells, HOT-A dose-dependently promoted primary human NK cell activation, cytokine production and cytotoxicity in the K562 cells. In the in vivo CT-26 tumor model, granzyme B+ NK cells in the TIL were significantly increased in the HOT-A treated tumor bearing mice and NK function gene signature was also increased by Nanostring analysis, suggesting an enhanced NK function in the tumor microenvironment. Taken together, the pre-clinical data presented here demonstrate that our CBL-B inhibitor enhances NK cell function in vitro and in vivo, suggesting that its enhancement of anti-tumor immunity may be driven through both effector T cell and NK cell-driven biology. Citation Format: Yilin Qi, Jun Kuai, Yingzhi Bi, David Greco, Samira Jaeger, Ken Carson, Hadi Danaee, Timothy Reilly, Geraldine Harriman, Fang Wang. Inhibition of the E3 ligase CBL-B enhances the effector function and proliferation of natural killer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB337.

Ovarian Stimulation in Mice Resulted in Abnormal Placentation through Its Effects on Proliferation and Cytokine Production of Uterine NK Cells.

Ovarian stimulation is associated with an increased incidence of abnormal placentation. Uterine natural killer (uNK) cells are the major subpopulation of decidual immune cells, which are crucial for placentation. In a previous study, we found that ovarian stimulation impairs uNK cell density on gestation day (GD) 8.5 in mice. However, it was not clear how ovarian stimulation led to a reduction in the density of uNK cells. In this study, we constructed two mouse models, an in vitro mouse embryo transfer model and an estrogen-stimulated mouse model. We used HE and PAS glycogen staining, immunohistochemical techniques, q-PCR, Western blot, and flow cytometry to analyze the mouse decidua and placenta, and the results showed that SO resulted in a fetal weight reduction, abnormal placental morphology, decreased placental vascular density, and abnormal density and function of uNK cells. Our results suggest that ovarian stimulation resulted in aberrant estrogen signaling and may contribute to the disorder of uNK cells caused by ovarian stimulation. Together, these results provide new insights into the mechanisms of aberrant maternal endocrine environments and abnormal placentation.

A Microphysiological Device to Model the Choriodecidual Interface Immune Status during Pregnancy.

During human pregnancy the chorion (fetal) lines decidua (maternal) creating the feto-maternal interface. Despite their proximity, resident decidual immune cells remain quiescent during gestation and do not invade the chorion. Infection and infiltration of activated immune cells toward the chorion are often associated with preterm birth. However, the mechanisms that maintain choriodecidual immune homeostasis or compromise immune barrier functions remain unclear. To understand these processes, a two-chamber microphysiological system (MPS) was created to model the human choriodecidual immune interface under normal and infectious conditions invitro. This MPS has outer (fetal chorion trophoblast cells) and inner chambers (maternal decidual + CD45+ cells [70:30 ratio]) connected by microchannels. Decidual cells were treated with LPS to mimic maternal infection, followed by immunostaining for HLA-DR and HLA-G, immune panel screening by imaging cytometry by time of flight, and immune regulatory factors IL-8 and IL-10, soluble HLA-G, and progesterone (ELISA). LPS induced a proinflammatory phenotype in the decidua characterized by a decrease in HLA-DR and an increase in IL-8 compared with controls. LPS treatment increased the influx of immune cells into the chorion, indicative of chorionitis. Cytometry by time offlight characterized immune cells in both chambers as active NK cells and neutrophils, with a decrease in the abundance of nonproinflammatory cytokine-producing NK cells and T cells. Conversely, chorion cells increased progesterone and soluble HLA-G production while maintaining HLA-G expression. These results highlight the utility of MPS to model choriodecidual immune cell infiltration and determine the complex maternal-fetal crosstalk to regulate immune balance during infection.

Ablation of SYK Kinase from Expanded Primary Human NK Cells via CRISPR/Cas9 Enhances Cytotoxicity and Cytokine Production.

CMV infection alters NK cell phenotype and function toward a more memory-like immune state. These cells, termed adaptive NK cells, typically express CD57 and NKG2C but lack expression of the FcRγ-chain (gene: FCER1G, FcRγ), PLZF, and SYK. Functionally, adaptive NK cells display enhanced Ab-dependent cellular cytotoxicity (ADCC) and cytokine production. However, the mechanism behind this enhanced function is unknown. To understand what drives enhanced ADCC and cytokine production in adaptive NK cells, we optimized a CRISPR/Cas9 system to ablate genes from primary human NK cells. We ablated genes that encode molecules in the ADCC pathway, such as FcRγ, CD3ζ, SYK, SHP-1, ZAP70, and the transcription factor PLZF, and tested subsequent ADCC and cytokine production. We found that ablating the FcRγ-chain caused a modest increase in TNF-α production. Ablation of PLZF did not enhance ADCC or cytokine production. Importantly, SYK kinase ablation significantly enhanced cytotoxicity, cytokine production, and target cell conjugation, whereas ZAP70 kinase ablation diminished function. Ablating the phosphatase SHP-1 enhanced cytotoxicity but reduced cytokine production. These results indicate that the enhanced cytotoxicity and cytokine production of CMV-induced adaptive NK cells is more likely due to the loss of SYK than the lack of FcRγ or PLZF. We found the lack of SYK expression could improve target cell conjugation through enhanced CD2 expression or limit SHP-1-mediated inhibition of CD16A signaling, leading to enhanced cytotoxicity and cytokine production.

The impact of BCG dose and revaccination on trained immunity

The innate immune system can display heterologous memory-like responses termed trained immunity after stimulation by certain vaccinations or infections. In this randomized, placebo-controlled trial, we investigated the modulation of Bacille Calmette-Guérin (BCG)-induced trained immunity by BCG revaccination or high-dose BCG administration, in comparison to a standard dose. We show that monocytes from all groups of BCG-vaccinated individuals exerted increased TNFα production after ex-vivo stimulation with various unrelated pathogens. Similarly, we observed increased amounts of T-cell-derived IFNγ after M. tuberculosis exposure, regardless of the BCG intervention. NK cell cytokine production, especially after heterologous stimulation with the fungal pathogen Candida albicans, was predominantly boosted after high dose BCG administration. Cytokine production capacity before vaccination was inversely correlated with trained immunity. While the induction of a trained immunity profile is largely dose- or frequency independent, baseline cytokine production capacity is associated with the magnitude of the innate immune memory response after BCG vaccination.

Immunodeficiency associated with a novel functionally defective variant of SLC19A1 benefits from folinic acid treatment.

Insufficient dietary folate intake, hereditary malabsorption, or defects in folate transport may lead to combined immunodeficiency (CID). Although loss of function mutations in the major intestinal folate transporter PCFT/SLC46A1 was shown to be associated with CID, the evidence for pathogenic variants of RFC/SLC19A1 resulting in immunodeficiency was lacking. We report two cousins carrying a homozygous pathogenic variant c.1042 G > A, resulting in p.G348R substitution who showed symptoms of immunodeficiency associated with defects of folate transport. SLC19A1 expression by peripheral blood mononuclear cells (PBMC) was quantified by real-time qPCR and immunostaining. T cell proliferation, methotrexate resistance, NK cell cytotoxicity, Treg cells and cytokine production by T cells were examined by flow cytometric assays. Patients were treated with and benefited from folinic acid. Studies revealed normal NK cell cytotoxicity, Treg cell counts, and naive-memory T cell percentages. Although SLC19A1 mRNA and protein expression were unaltered, remarkably, mitogen induced-T cell proliferation was significantly reduced at suboptimal folic acid and supraoptimal folinic acid concentrations. In addition, patients' PBMCs were resistant to methotrexate-induced apoptosis supporting a functionally defective SLC19A1. This study presents the second pathogenic SLC19A1 variant in the literature, providing the first experimental evidence that functionally defective variants of SLC19A1 may present with symptoms of immunodeficiency.

CD160 receptor in CLL: Current state and future avenues.

CD160 is a glycosylphosphatidylinositol (GPI)-anchored cell surface glycoprotein expressed on cytotoxic natural killer (NK) cells and T-cell subsets. It plays a crucial role in the activation of NK-cell cytotoxicity and cytokine production. It also modulates the immune system and is involved in some pathologies, such as cancer. CD160 is abnormally expressed in B-cell chronic lymphocytic leukemia (CLL) but not expressed in normal B lymphocytes. Its expression in CLL enhances tumor cell proliferation and resistance to apoptosis. CD160 is also a potential prognostic marker for the detection of minimal residual disease (MRD) in CLL, which is important for theclinical management of CLL, the prevention of disease relapse, and the achievement of complete remission. In this review, we present an overview of CD160 and its involvement in the pathophysiology of CLL. We also discuss its use as a prognostic marker for the assessment of MRD in CLL.

NK cell-mediated immunostimulatory effects of ethanol extract of Morinda citrifolia (noni) fruit

BackgroundMorinda citrifolia (Noni) is a plant that has long been used in various products such as foods and cosmetics. Although noni has been known to have immunostimulatory activity, detailed mechanism at the cellular level has not been fully elucidated yet. In this study, we focused on understanding as to how noni fruit can positively stimulate body’s immune responses.MethodsTo do this, an ethanol extract of noni fruit (Mc-fEE) was prepared and administered for 30 days to male C57BL/6 mice for in vivo experiment. NK cell activity and cytokine production level from Mc-fEE-treated mice were analyzed by flowcytometry, real-time PCR, and ELISA. Mc-fEE-triggered molecular events were detected from RAW264.7 cells and splenocytes using Western blotting and real-time PCR analyses.ResultsThe mRNA expression levels of cytokines such as interleukin families, interferon (IFN)-β, and tumor necrosis factor (TNF)-α were increased by Mc-fEE treatment in vitro and in vivo. Western blotting analysis showed that the phosphorylation levels of nuclear factor (NF)-κB and activator protein (AP)-1 subunits these were enhanced in Mc-fEE-treated RAW264.7 cells. In addition, according to in vivo experiments, it was considered that Mc-fEE can increase the population of splenic NK cells and subsequent upregulation of their cytotoxic activity against YAC-1 cells, a T- cell lymphoma.ConclusionIn this paper, we could confirm that Mc-fEE has remarkable immunostimulatory effects by activation and increase of the NK cell population.

Abstract 2878: Mediating NK cell function against solid tumors, via targeting of tumor stroma, using a TEM8-targeting Tri-specific Killer Engager (TriKE®)

Abstract Immunotherapies for solid tumors need to overcome barriers within the solid tumor microenvironment (TME), including stromal cells, cancer-associated fibroblasts, endothelial cells, pericytes, and immune cells. These can comprise a significant portion of the tumor mass in many common carcinomas and contribute to immune cell dysfunction within the tumor. Stromal cells support cancer cells through several mechanisms and can promote metastasis. Tumor vasculature supplies cancer cells with nutrients and oxygen necessary for tumor growth and dissemination. Thus, targeting these components of cancer can enhance tumor rejection directly and increase sensitization of surviving tumors to immune infiltration and chemotherapeutic treatments through weakening of the tumor architecture. While there are current antiangiogenic therapies being tested clinically, they have associated toxicities in normal angiogenic processes, limiting clinical efficacy. Tumor Endothelial Marker 8 (TEM8, encoded by the ANTXR1 gene) is a highly conserved integrin-like adhesion molecule that was discovered on the endothelium of colorectal cancer, and subsequent studies identified its expression on multiple stromal cells—endothelial cells, fibroblasts, and pericytes—in the tumor microenvironment of diverse human cancer types. Little to no expression has been demonstrated in normal human stroma, indicating that this would be a good target for immunotherapy. Using a mammalian expression system, we designed and expressed a TEM8 targeting TriKE (cam1615TEM8) consisting of a humanized anti-CD16 single domain antibody, a wild-type IL-15 moiety, and an anti-TEM8 scFv. cam1615TEM8 induces NK cell degranulation and cytokine production against TEM8+ tumor and stromal cell lines (endothelial cells and fibroblasts). Using TEM8- cancer lines and a TEM8-CRISPR knockout version of A549 lung cancer lines, we show that cam1615TEM8 only activates NK cells in the presence of tumor antigen. cam1615TEM8 also preferentially stimulates TEM8+ tumor spheroid killing. Moreover, the camelid anti-CD16 nanobody selectively enhances signaling by the IL-15 moiety to NK cells, specifically promoting NK cell survival and proliferation in vitro and in vivo. In an in vivo xenogeneic mouse model, containing human NK cells and tumor, cam1615TEM8-treated mice had enhanced NK cell tumor infiltration, significantly decreased tumor growth, and enhanced survival when compared to IL-15 treated mice. Since TEM8 is highly conserved, and the scFv within the TriKE is reactive to mouse TEM8, we were able to show reduced tumor endothelial density in the tumors of mice treated with cam1615TEM8. Given the findings of this study cam1615TEM8 could be leveraged in several clinical settings by inducing NK cell specific targeting of the tumor itself and/or the tumor endothelium and stroma. Citation Format: Martin Felices, Michael Kaminski, Peter Hinderlie, Rachel Hopps, Laura Bendzick, Melissa Geller, Jeffrey S. Miller. Mediating NK cell function against solid tumors, via targeting of tumor stroma, using a TEM8-targeting Tri-specific Killer Engager (TriKE®) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2878.

Enhanced Proinflammatory Cytokine Production and Immunometabolic Impairment of NK Cells Exposed to Mycobacterium tuberculosis and Cigarette Smoke.

AimSmoker COPD patients with chest radiological signs of prior tuberculosis (TB) showed more severe lung damage, but the mechanisms remain unclear. Emerging evidence has implicated NK cells in the pathogenesis of both COPD and TB. The purpose of this study was to delineate the profile and cytokine production of NK-cell subpopulations and their immunometabolic changes after exposure to both cigarette smoke (CS) and Mycobacterium tuberculosis(MTB).MethodsWe profiled NK-cell subpopulations in terms of percentage and cytokine production by flow cytometry in smoker patients with pulmonary TB (PTB). In an in vitro coexposure model, we investigated proinflammatory cytokine production, glycolytic influx, and oxidative phosphorylation of NK cells under CS extract (CSE) and PPD costimulation.ResultsPeripheral blood NK cells in smoker patients with active PTB (CS+PTB group) showed altered proportion of subpopulations and excessive proinflammatory cytokine expressions. In vitro, CSE- and PPD-coexposed NK-92 cells displayed enhanced proinflammatory cytokine production, concurrent with decreased glycolytic influx and oxidative phosphorylation.ConclusionSmoker patients with active PTB showed enhanced proinflammatory cytokine expression within altered NK cell subpopulations. CSE and PPD coexposure induced heightened cytokine production concurrent with impaired cell metabolism in NK cells. These novel data suggest a potential role of NK cells in the pathogenesis of lung injury in subjects with coexposure to CS and TB.

Особенности иммунореактивности организма в постковидном периоде у полиморбидных пациентов с хроническими очагами инфекции ЛОР-органов и полости рта

The high level of morbidity and labor losses among the population during the epidemic of a new coronavirus infection is largely determined by the protracted course of the post-COVID syndrome, which is often complicated by the exacerbation of chronic foci of infection of the upper respiratory tract and oral cavity. Clinical manifestations of a developed immunodeficiency state require an assessment of the characteristics of the body’s immunoreactivity in patients who have undergone COVID-19 in order to develop targeted programs for their immunorehabilitation and prevent manifestations of chronic focal infection, which was the purpose of the study. Immunological examination of 37 patients aged 42 to 60 years (53 ± 3.8 years), 24 women and 13 men, in the post-COVID period with exacerbation of chronic ENT infection (nasopharyngitis, sinusitis, otitis media, laryngitis) and dental pathology (generalized inflammatory periodontal disease, apical granulomas) showed the formation of an immunological imbalance with a quantitative deficiency of T-helpers with a high level of cytotoxic T-lymphocytes and NK cells expressing the alpha chain of the CD8 antigen as well as cytokine-producing NK cells against the background of a pronounced decrease in the resources of alpha and gamma interferon and a high level of Ig E and CIC in the blood. The established immunological prerequisites for comorbid infection, allergization, autoimmunization, and chronic sequel of inflammatory response motivated approaches to the rehabilitation of patients in the post-COVID period and the prevention of activation of chronic foci of infection in the ENT organs and oral cavity through sequential detoxification and immunocorrection. The positive experience of using bioactive preparations of natural origin with a complex detoxifying, immunotropic, antioxidant, and adaptogenic action is presented.

Analysis of NKp46 expression and cytokine production in decidual NK cells – Possibility to predict recurrent pregnancy loss

Analysis of NKp46 expression and cytokine production in decidual NK cells – Possibility to predict recurrent pregnancy loss

Immune checkpoint markers and anti-CD20-mediated NK cell activation.

Anti-CD20 mAb is an effective therapy for most B-cell malignancies. Checkpoint blockade has been used to enhance T-cell-mediated antitumor response. Little is known about the biologic significance of immune checkpoints expressed by NK cells in anti-CD20-based therapy. To investigate the role of checkpoints in anti-CD20-mediated NK cell biology, Raji B-cell lymphoma cells, and PBMCs from normal donors were cocultured with rituximab (RTX), obinutuzumab (OBZ), or trastuzumab as a control mAb for between 20h and 9 d. RTX and OBZ induced a dose-dependent NK cell up-regulation of T-cell immunoreceptor with Ig and ITIM domain (TIGIT) and T-cell immunoglobulin mucin-3 (TIM3), but not PD1, CTLA4, or LAG3. Resting CD56dim NK had higher TIGIT and TIM3 expression than resting CD56bright NK although TIGIT and TIM3 were up-regulated on both subsets. NK cells with the CD16 158VV single nucleotide polymorphism had greater TIM3 up-regulation than did NK from VF or FF donors. TIGIT+ and TIM3+ NK cells degranulated, produced cytokines, and expressed activation markers to a greater degree than did TIGIT- or TIM3- NK cells. Blockade of TIGIT, TIM3, or both had little impact on RTX-induced NK cell proliferation, degranulation, cytokine production, or activation. Taken together, TIGIT and TIM3 can serve as markers for anti-CD20-mediated NK cell activation, but may not serve well as targets for enhancing the anti-tumor activity of such therapy.

Recurrent Mutations of the C-C Motif Chemokine Ligand 22 (CCL22) Define a Distinct Subgroup of Chronic Lymphoproliferative Disorder of NK Cells (CLPD-NK)

Background: The pathogenesis of chronic lymphoproliferative disorder of NK-cells (CLPD-NK) is poorly understood. Mutations in the JAK/STAT pathway (especially STAT3) are found in 30% of patients, but the genetic or exogenous drivers responsible for other cases are unknown. Here we comprehensively define the genetic drivers of CLPD-NK by integrated genome and transcriptome sequencing (WGS/WTS) of a large cohort of cases and complementary functional analyses. Methods: We studied 63 CLPD-NK patients (M/F: 42/21, median age: 71 years [35-89 y]) by WGS, WTS and flow cytometry. A validation cohort of 67 patients (M/F: 43/24, median age: 64 years [7-91]) was analyzed by targeted sequencing. To study the role of CCL22 in CLPD-NK pathogenesis, we examined internalization of the CCL22 receptor, CCR4, and cell chemotaxis in response to exogenous wild type (wtCCL22) or mutant CCL22 (mtCCL22: L45R, P79R, IL87_88NF) in CCR4-expressing Ba/F3 cells (Ba/F3-CCR4). To examine potential autocrine/paracrine activity, we exchanged supernatants of Ba/F3-CCR4-wtCCL22 and -mtCCL22 cells and examined CCR4 expression. To examine the in vivo effects of the mutations on proliferation and phenotype, GFP-tagged empty vector, wtCCL22, or mtCCL22-transduced NK-92 cells were engrafted into IL15-transgenic NOD.Cg-Prkdcscid Il2rgtm1Wjl Tg(IL15)1Sz/SzJ (NSG) mice. Human NK-92 cells isolated from spleens of moribund mice were analyzed by WTS and immunophenotyping. Results: WGS of 63 CLPD-NK identified STAT3 mutations in 18 (29%) cases, with mutually exclusive CCL22 mutations (mtCCL22) in 14 (22%) patients. WGS of 4500 hematological malignancies showed that mtCCL22 were only found in CLPD-NK. Recurrent co-mutations in both groups were found in ATM (n=3), FAS (n=2) and TET2 (n=5). Of the remaining patients, 23/31 had one or more mutation including epigenetic regulators (n=12), signaling components (n=7) or TP53 (n=4). Our findings of CCL22 mutations were confirmed in an independent validation cohort with STAT3 mutations in 19/67 (28%) and mtCCL22 in 13/67 (19%). CCL22 mutations were clustered at the conserved leucine 45 and proline 79 residues (Fig. 1A). Sequencing of purified CD3+ T and CD56+ NK cells showed that the mtCCL22 were somatic mutations acquired by the CD56+ NK population. mtCCL22 defined a subgroup of CLPD-NK, with high NCAM1 (CD56) positivity by flow cytometry (p<0.001) and WTS (log2 fold change 2.89, adjusted P<0.0001). The gene expression profile of mtCCL22 CLPD-NK closely resembled that of CD56bright NK cells, and was characterized by enrichment of cytokine- and chemokine-mediated signaling and inflammatory response pathways (P<0.001, each). Among the 31 genes significantly up-regulated in mtCCL22 patients (log2FC > 1.3, adj P<0.05, Fig. 1B), we found XCL1/2, which are potent chemoattractants. CCL22 induces chemotaxis of CCR4-expressing Th2 T cells, and also drives CCR4 internalization mediated by G-protein coupled receptor signaling via β-arrestin as a negative feedback mechanism. All three tested mtCCL22 resulted in significant and prolonged attenuation of CCR4 internalization compared to wtCCL22 (Fig 1C). Exchanging the supernatant of mtCCL22-treated Ba/F3-CCR4 cells for that from wtCCL22-treated cells decreased CCR4 expression, and vice versa, suggesting that mtCCL22 regulates CCR4 surface expression and signaling through an autocrine or paracrine mechanism (Fig 1D). Furthermore, mtCCL22 increased chemotaxis of CCR4-Ba/F3 cells in a transwell cell migration assay compared to wtCCL22 (Fig 1E). Expression of mtCCL22 enhanced engraftment of NK-92 cells which exhibited higher XCR1,GZMK and surface CD56 expression compared to controls, as well as deregulation of type I interferon response pathways indicating reactive cytokine production similar to that observed in CLPD-NK patients. Conclusions: mtCCL22 were detected in 19-22% of CLPD-NK, were mutually exclusive with STAT3 mutations, and define a distinct subgroup of CLPD-NK with genetic features that recapitulate CD56bright cytokine-producing NK cells. We show that mtCCL22 enhanced cellular chemotaxis by preventing CCR4 internalization and promoted expansion of CD56+ NK cells in vivo. We recommend to study mtCCL22 in cases suspected of CLPD-NK, in order to distinguish clonal NK neoplasms from polyclonal reactive expansion. Disclosures Feith: Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees. Loughran:Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bioniz Therapeutics: Membership on an entity's Board of Directors or advisory committees; Keystone Nano: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Mullighan:Pfizer: Honoraria, Research Funding, Speakers Bureau; Illumina: Consultancy, Honoraria, Speakers Bureau; AbbVie, Inc.: Research Funding.